Telephone-transmitter



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TELEPHONE TRANSMITTER- No. 513,730. Patented Jan. 30, 1894,-

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' F. H. RICHARDS.

TELEPHONE TRANSMITTER.

Patented Jan. 30,1894.-

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UNITED STATES PATENT. -OFFICE.

FRANCIS HLR ICHAR'DS, OF HARTFORD, CONNECTICUT.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 513,730, dated January 30, 1894.

Application filed July 31,1893. Serial No. 481,937. (No model.)

To all whom it may concern.-

Be it known that I, FRANCIS H. RICHARDS, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain ilewand useful Improvements in Telephone-Transinitters, of which the following is a specifica- This invention relates to transmitters for electric speaking telephones; the object bemg to furnish an improved instrument of this class, in which the required undulatory currents may be produced by variations of the current-strength resulting from a variation in the amount of contact between surfacecontacting electrodes. In the drawings accompanying and formmg a part of this specification, Figure 1 is a sectional plan view of a telephone transmitter made according to my present invention; Fig. 2 is a front sectional elevation of the same, on line aa, Fig. 1. Fig. 3 is a transverse sectional view on line bb, Fig. 2. Fig. 4 is an enlarged front view of the follower electrode and its carrier, and Fig. 5 is a sectional view of the same on line dd, Fig. 4. Fig. 6 is an enlarged top view of one form of the vibrator electrode and itscarrier, and Fig. 7 is an end-view of the same. Figs. 8 and 9 are partial plan views, similar to a portion of Fig. 1, for illustrating the operation FigsxlO and 11 are plan views similar to Fig. 1, for illustrating modified forms of the transmitter. I

Similar characters designate like parts in all the figures.

My improved telephonic instrument consists of a suitable framework, a plate sensitive to sound-waves, one electrode having a compound working-face, a-follower electrode bearing upon the working-face of the other electrode, and means operatively connecting one of the electrodes with the plate "so that the vibratory action of the plate operates to vary the amount of contact between the electrodes by sliding one of these uponthe other in the direction of their electrical contacting surfaces. 7

In the drawings, I have shown the vi brator electrode provided with said compound working-face and operatively connected with the plate so that the workingface and electrode partake of the vibratory action of the plate and move against the follower-electrode.

The frame F may be of any convenient description, being preferably of box-like form, and consisting of the four sides 2, 3, 4 and 5, the front-plate 6, and the back-plate 7, all suitably held together. The diaphragm, or sensitive plate, 8, is fixed in place just within the front-plate, after the ordinary manner of supporting the sensitive plates of telephonic instruments, and a mouth-piece, 9, is or may be provided around the aperture 10, of the front-plate for directing the sound-waves against the diaphragm. This plate and some suitable connection therewith, constitute the means for actuating the vibrator-electrode, as hereinafter more fully set forth.

The vibrator, or compound-electrode, which is designated in a general way by B, consists (as shown in Figs. 1 to 10, inclusive) of an electrode, 11, and a non-conducting element, 12, whose workingsurface 12 constitutes a true extension of the working-surface 11 of the electrode. These two working surfaces constitutethe working-face. This vibrator may be fixed to the diaphragm directly, as shown in Fig. 10; or, it may be carried upon the end of the lever or vibration-multiplier, 13, as shown in Figs. 1, 2 and 3, supported at 14, on the back-plate 7 of the frame. Said vibrator-lever 13 is shown having therein a reduced portion 13, constituting a springpivot, and is connected at 15 by the connecting-piece 16 and pivot 17, with the middle portion of the sensitive plate 8. By this means, the movement of the vibrator is multiplied over that of the plate itself, for the purpose of increasing the variation in the amount of contact between the two electrodes and thus increasing the variation in current-strength and the resultant electrical undulations for transmitting speech. The compound vibrator-electrode may be carried directly upon the diaphragm; according to the modification illustrated in Fig. 10; and this arrangement of the two electrodes may be reversed, as in Fig. 11, all within the scope of my invention.

The electrodes are usually and preferably of carbon, and one of them has contiguous thereto a non-conducting element, 12, of suitable substance, as hard-rubber, glass or the llke, fixed beside of the electrode, and formmg together therewith a continuous workingsurface or vibrator-face comprising two portlons or fields of which one, 11, Fig. 6, is the electrical field, and the other 12, is the the non-electrical field. The two elements 11 and 12 are conveniently held together in the bifurcated end of the lever 13, by means of the ordinary binding-screw 18.

The follower consists of an electrode 19, similar to that of the vibrator, and is sup ported to bear against the vibrator but not to partake of the reciprocatory or vibrating movements thereof; said electrode 19 is pivotally supported in a carrier 20, upon the upper end of the spring 20 which carries said follower, but, being set edgewise to the normal movement of the vibrator, does not perinlt said follower to partake of the vibratory movements of the vibrator. Said followercarrying spring 20 is shown fixed at 21 to the framework of the instrument, and an adjustlngscrew, 22, is shown bearing against said spring for the purpose of adjusting the tension of the same.

The follower-electrode is shown set to bring it by the greater part of its width to one side of the vibrator-electrode5 the follower-electrode, however, bears with its entire surface against the aforesaid working-face 12 of the vibrator, so that the pressure upon any given area of either electrode is not materially increased or dimished by the sliding action of the one upon the other; the proper uniform pressure of the follower against the vibrator being maintained by the follower-carrying spring.

The action of the voice upon the diaphragm 8 imparts thereto a vibratory movement which is transmitted through the connection 16 and the lever 13 (when the lever is used) to the vibrator-electrode 11, imparting to this a relatively considerable movement. The opera tion of the vibrator-electrode against the face of the follower-electrode 19 carries the same laterally of the opposite contacting terminal 12 to reduce and increase alternately the extent .of the surface-contact between said electrodes, as illustrated in Figs. 8 and 9, respect ively. This variation of the amount of contact between the electrodes causes a variation in the current-strength passing through the same, and thereby, probably by varying the heat of the carbons, gives rise to the undulatorycurrentsrequired for transmittingspeech.

According to my present invention, the relative distance between the electrodes 11 and 19 need not be variable, but the working variation is restricted to the amount of contact between the electrodes, and this variation of surface-contact is effected by a movement of one electrode upon the other in the plane of their contacting surfaces.

The modification illustrated in Fig. 11 is not specifically claimed herein, but constitutes in part the subject-matter of aseparate application, Serial No. 492,698, filed December 4, 1893.

Having thus described my invention, I claim- 1. In a telephonic transmitter, the combination with a plate sensitive to sound-waves, of a vibration multiplier operatively connected with the plate, a compound electrode substantially as described, carried by said multiplier and having a working-face comprising an electrical and a non-electrical field, and an electrode bearing against said working-face and extending onto both the said fields, and having its working movement in the direction of said working face, substantially as described.

2. In a telephonic transmitter, the combination with a plate sensitive to sound-waves and with the compound electrode operatively connected therewith and having a workingface comprising an electrical and a non-electrical field, of the opposite electrode bearing against said working-face and having a supporting pivot, and an electrode-carrier supporting said electrode by its pivot to bear against said working-face, substantially as described and for the purpose specified.

3. In a telephonic-transmitter, the combination with the compound electrode having two fields substantially as described and adapted to have a vibratory movementin the direction of the field-surfaces, of means for actuating the compound electrode fromsound- Waves, and a non-vibratory electrode held in contact with the compound'electrode and extending onto both of said fields, substantially as set forth.

FRANCIS I-I. RICHARDS.

Witnesses:

FRED. J. DOLE, J OHN L. EDWARDS, J R.

ICO 

